Indicator Assessment

Distribution of marine species

Indicator Assessment
Prod-ID: IND-102-en
  Also known as: CLIM 015
Published 20 Nov 2012 Last modified 11 May 2021
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  • Increases in regional sea temperatures have triggered a major northward expansion of warmer-water plankton in the North-east Atlantic and a northward retreat of colder-water plankton. This northerly movement is about 10 ° latitude (1 100  km) over the past 40 years, and it seems to have accelerated since 2000.
  • Sub-tropical species are occurring with increasing frequency in European waters, and sub-Arctic species are receding northwards.
  • Further changes in the distribution of marine species are expected, with projected further climate change, but quantitative projections are not available.

Calanus ratio in the North Sea

Note: Continuous Plankton Recorder data. Left: Temporal and seasonal distribution of the Calanus ratio (1958–2009). Right: Change in Calanus ratio in the North Sea between (1958 and 2009).

Data source:

Past trends

Increases in regional sea temperatures have triggered a major northward movement of warmer-water plankton in the North-east Atlantic and a similar retreat of colder-water plankton to the north. This northerly movement is about 10 o latitude (1 100 km) over the past 40 years (a mean poleward movement of between 200 and 250 km per decade), and there appears to have been an acceleration since 2000 [i]. Recently, a Norwegian study showed even faster rates of northward movement between 1997 and 2010. Out of about 1 600 benthic marine species found in coastal waters of southern Norway, 565 species had expanded their distribution northwards along the coast, at rates of 500–800 km per decade [ii]. These rates are much faster than any other documented terrestrial study.


Further changes in the distribution of marine species are expected with projected further climate change, but quantitative projections are not available.

[i] Grégory Beaugrand, „Decadal changes in climate and ecosystems in the North Atlantic Ocean and adjacent seas“, Deep Sea Research Part II: Topical Studies in Oceanography 56, Nr. 8–10 (April 2009): 656–673, doi:10.1016/j.dsr2.2008.12.022.

[ii] T. Brattegard, Endringer i norsk marin bunnfauna 1997-2010 DN-utredning 8-2011 (Trondheim: Direktoratet for naturforvaltning, 2011),

Supporting information

Indicator definition

  • Calanus ratio in the North Sea
  • Annual mean number of Calanus per sample


  • Ratio [dimensionless]
  • Number of Calanus [dimensionless]


Policy context and targets

Context description

In April 2013 the European Commission presented the EU Adaptation Strategy Package ( This package consists of the EU Strategy on adaptation to climate change /* COM/2013/0216 final */ and a number of supporting documents. One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which should occur through Bridging the knowledge gap and Further developing Climate-ADAPT as the ‘one-stop shop’ for adaptation information in Europe. Further objectives include Promoting action by Member States and Climate-proofing EU action: promoting adaptation in key vulnerable sectors. Many EU Member States have already taken action, such as by adopting national adaptation strategies, and several have also prepared action plans on climate change adaptation.

The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.


No targets have been specified.

Related policy documents

  • Climate-ADAPT: Adaptation in EU policy sectors
    Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
  • Climate-ADAPT: Country profiles
    Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
  • DG CLIMA: Adaptation to climate change
    Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives in the future. This web portal provides information on all adaptation activities of the European Commission.
  • EU Adaptation Strategy Package
    In April 2013, the European Commission adopted an EU strategy on adaptation to climate change, which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it enhances the preparedness and capacity of all governance levels to respond to the impacts of climate change.


Methodology for indicator calculation

Data from the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) on Calanus abundance in the central North Sea 1958–2009 is used for the indicator. The Continuous Plankton Recorder (CPR) survey is the longest running, large-scale marine biological survey in the world. The CPR is a near-surface (10 m) plankton sampler voluntarily towed each month behind merchant ships on their normal routes of passage. Methods of analysis for, 400 phyto and zooplankton taxa have remained almost unchanged since 1958.

Methodology for gap filling

Not applicable

Methodology references



Methodology uncertainty

Not applicable

Data sets uncertainty

In general, changes related to the physical and chemical marine environment are better documented than biological changes because links between cause and effect are better understood and often time series of observations are longer. The longest available records of plankton are from the Continuous Plankton Recorder (CPR) are some 60 years long. It is a sampler that is towed behind many different merchant vessels, along fixed shipping routes. Sampling was started in the North Sea in the 1950s and today a network covering the entire north Atlantic has been established. No other plankton time series of equivalent length and geographical coverage exist for the European regional seas, although many new initiatives investigating species distributions and their changes in Europe’s seas are now emerging.

Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012 (

Rationale uncertainty

No uncertainty has been specified

Data sources

Other info

DPSIR: Impact
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CLIM 015
Frequency of updates
Updates are scheduled every 4 years
EEA Contact Info


Geographic coverage

Temporal coverage



Filed under:
Filed under: climate change
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